Vibration motors (or “vibration actuators”) are built into mobile electronic devices, and are broadly used as devices to communicate to the user, through a vibration, that there is an incoming call, or that a signal, such as an alarm, has been generated, and have become indispensable devices in wearable devices, which are carried on the body of the user. Moreover, in recent years vibration motors have been of interest as devices by which to achieve haptics (skin-sensed feedback) in the human interfaces such as touch panels.
Among the various forms of vibration motors that are under development, there is interest in linear vibration motors that are able to generate relatively large vibrations through linear reciprocating vibrations of a movable element. A conventional linear motor is provided with a weight and a magnet on a movable element side, where an electric current is applied to a coil that is provided on the stator side to cause the Lorentz forces that act on the magnet to form a driving force, to cause the movable element, which is elastically supported along the direction of vibration, to undergo reciprocating vibrations in the axial direction. There is a known conventional linear vibration motor of this type, wherein a shaft is disposed along the direction of vibration, and coil springs are disposed on both sides, in the direction of vibration, of the movable element, to cause the movable element to vibrate while the guided by the shaft (See, for example, Japanese Unexamined Patent Application Publication No. 2016-13554).